Phosphorescent material, process for producing phosphorescent material, and phosphorescent element

Abstract

Provided are a phosphorescent material which is excellent in horizontal orientation and the like when a thin film is formed, a process for efficiently producing the phosphorescent material, and a light emitting element using the phosphorescent material. The present invention provides a phosphorescent material represented by the following general formula (1), a process for producing the phosphorescent material, and a light emitting element using the phosphorescent material, wherein the phosphorescent material has a straight-chain conjugated structure, a 2-phenylpyridine ligand, a central metal and a β-diketone-type ligand, In the general formula (1), end substituents R 1 and R 2 each is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or the like, substituents a to l and o to s each is a hydrogen atom or the like, the central metal M is platinum or the like, and repetition numbers m and n each is an integer of 0 to 4.

1 . A phosphorescent material represented by the following general formula (1), wherein the phosphorescent material comprises a straight-chain conjugated structure, a 2-phenylpyridine ligand, a central metal and a β-diketone-type ligand, 
       
         
           
           
               
               
           
         
       
       wherein in the general formula (1), end substituents R 1  and R 2  are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a halogen atom, a substituted or unsubstituted boryl group, or a substituted or unsubstituted amino group, substituents a to l and o to s are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a halogen atom, the central metal M is platinum (Pt), iridium (Ir), nickel (Ni), copper (Cu) or gold (Au), repetition numbers m and n are each independently an integer of 0 to 4, and m+n is an integer of 2 or greater. 
     
     
         2 . The phosphorescent material according to  claim 1 , wherein the R 1  and R 2 , or any one thereof, in the general formula (1), are a tertiary butyl group. 
     
     
         3 . The phosphorescent material according to  claim 1 , wherein a Stokes shift is set to a value of 130 nm or more. 
     
     
         4 . The phosphorescent material according to  claim 1 , wherein the phosphorescent material represented by the general formula (1) is at least one of compounds represented by the following structural formulae (2) to (7). 
       
         
           
           
               
               
           
         
       
     
     
         5 . A process for producing a phosphorescent material represented by the following general formula (1) and having a straight-chain conjugated structure, a 2-phenylpyridine ligand, a central metal and a β-diketone-type ligand, wherein the process comprises steps of: providing a binuclear complex represented by the following general formula (11); and acetylacetonating the binuclear complex, 
       
         
           
           
               
               
           
         
       
       wherein in the general formula (1), end substituents R 1  and R 2  are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a halogen atom, a substituted or unsubstituted boryl group, or a substituted or unsubstituted amino group, substituents a to l and o to s are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a halogen atom, the central metal M is platinum (Pt), iridium (Ir), nickel (Ni), copper (Cu) or gold (Au), repetition numbers m and n are each independently an integer of 0 to 4, and m+n is an integer of 2 or greater, 
       
         
           
           
               
               
           
         
       
       wherein in the general formula (11), a plurality of end substituents R 1  and R 2  is each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a halogen atom, a substituted or unsubstituted boryl group, or a substituted or unsubstituted amino group, a plurality of substituents a to l and o to s is each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a halogen atom, a plurality of central metals M is each independently platinum (Pt), iridium (Ir), nickel (Ni), copper (Cu) or gold (Au), a plurality of repetition numbers m and n is each independently an integer of 0 to 4, and m+n is an integer of 2 or greater. 
     
     
         6 . The process for producing a phosphorescent material according to  claim 5 , wherein the process comprises a step of obtaining the binuclear complex represented by the general formula (11) by synthesizing a straight-chain aryl compound including a pyridine structure, followed by performing a heat treatment in the presence of potassium tetrachloroplatinate and acetic acid. 
     
     
         7 . A light emitting element which comprises a light emitting layer or a plurality of organic thin film layers including the light emitting layer between a pair of electrodes including an anode and a cathode, wherein the light emitting layer comprises a host material as a main component and, as a dopant material, a phosphorescent material represented by the following general formula (1) and having a straight-chain conjugated structure, a 2-phenylpyridine ligand, a central metal and a β-diketone-type ligand, 
       
         
           
           
               
               
           
         
       
       wherein in the general formula (1), end substituents R 1  and R 2  are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a halogen atom, a substituted or unsubstituted boryl group, or a substituted or unsubstituted amino group, substituents a to l and o to s are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a halogen atom, the central metal M is platinum (Pt), iridium (Ir), nickel (Ni), copper (Cu) or gold (Au), repetition numbers m and n are each independently an integer of 0 to 4, and m+n is an integer of 2 or greater. 
     
     
         8 . The light emitting element according to  claim 7 , wherein the mixed quantity of the phosphorescent material is set to a value ranging from 0.1 to 20% by weight based on the total amount of the light emitting layer. 
     
     
         9 . A phosphorescent material represented by the following general formula (1a), wherein the phosphorescent material comprises a straight-chain conjugated structure, a 2-phenylpyridine ligand, a central metal and a β-diketone-type ligand, 
       
         
           
           
               
               
           
         
       
       wherein in the general formula (1a), end substituents R 1  and R 2  are each independently a substituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a halogen atom, a substituted or unsubstituted boryl group, or a substituted or unsubstituted amino group, substituents a to l and o to s are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a halogen atom, the central metal M is platinum (Pt), iridium (Ir), nickel (Ni), copper (Cu) or gold (Au), repetition numbers m and n are each independently 0 or 1, and m+n is 1. 
     
     
         10 . The phosphorescent material according to  claim 9 , wherein the phosphorescent material represented by the general formula (1a) is at least one of the compounds represented by the following structural formulae (8) to (10): 
       
         
           
           
               
               
           
         
       
     
     
         11 . A process for producing a phosphorescent material represented by the following general formula (1a) and having a straight-chain conjugated structure, a 2-phenylpyridine ligand, a central metal and a β-diketone-type ligand, wherein the process comprises steps of: providing a binuclear complex represented by the following general formula (11a); and acetylacetonating the binuclear complex, 
       
         
           
           
               
               
           
         
       
       wherein in the general formula (1a), end substituents R 1  and R 2  are each independently a substituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a halogen atom, a substituted or unsubstituted boryl group, or a substituted or unsubstituted amino group, substituents a to l and o to s are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a halogen atom, the central metal M is platinum (Pt), iridium (Ir), nickel (Ni), copper (Cu) or gold (Au), repetition numbers m and n are each independently an integer of 0 or 1, and m+n is 1, 
       
         
           
           
               
               
           
         
       
       wherein in the general formula (11a), a plurality of end substituents R 1  and R 2  is each independently a substituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a halogen atom, a substituted or unsubstituted boryl group, or a substituted or unsubstituted amino group, a plurality of substituents a to l and o to s is each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a halogen atom, a plurality of central metals M is each independently platinum (Pt), iridium (Ir), nickel (Ni), copper (Cu) or gold (Au), a plurality of repetition numbers m and n is each independently an integer of 0 or 1, and m+n is 1. 
     
     
         12 . A light emitting element which comprises a light emitting layer or a plurality of organic thin film layers including the light emitting layer between a pair of electrodes including an anode and a cathode, wherein the light emitting layer comprises a host material as a main component and, as a dopant material, a phosphorescent material represented by the following general formula (1a) and having a straight-chain conjugated structure, a 2-phenylpyridine ligand, a central metal and a β-diketone-type ligand, 
       
         
           
           
               
               
           
         
       
       wherein in the general formula (1a), end substituents R 1  and R 2  are each independently a substituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, a halogen atom, a substituted or unsubstituted boryl group, or a substituted or unsubstituted amino group, substituents a to l and o to s are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a halogen atom, the central metal M is platinum (Pt), iridium (Ir), nickel (Ni), copper (Cu) or gold (Au), repetition numbers m and n are each independently an integer of 0 or 1, and m+n is 1.